Dopamine dynamics in the basolateral amygdala during associative learning and exploration

Abstract

Dopamine release in the basolateral amygdala (BLA) is thought to contribute to salience attribution and associative learning; yet its role during self-paced behaviours has remained unexplored. Using fibre photometry combined with the genetically encoded dopamine sensor dLight1.1, I monitored real-time dopamine dynamics in freely moving mice during discriminative fear conditioning, extinction, and multiple exploratory paradigms. By aligning signals to both sensory cues and pose-estimated behaviours, I show that BLA dopamine transients are evoked not only by aversive unconditioned (US) and conditioned stimuli (CS+), but also during self-paced exploratory behaviours such as open arm entries, head dips, and rearing. In contrast, dopamine release was suppressed during non-exploratory or defensive states. Critically, BLA dopamine release was independent of speed, indicating a state-reflective rather than a movement-driven signal. During target-directed exploration (i.e., object or social stimulus), I implemented a vector-based classification of body orientation and proximity, which revealed that dopamine release in the BLA scales with both proximity to and orientation towards the target. BLA dopamine was differentially modulated by stimulus identity, with proximity to objects evoking a stronger dopamine release compared to proximity to social targets. Sensory cues and behavioural states were hierarchically ranked by signal magnitude, with stronger dopamine signals for highly salient cues (e.g., US and CS+), intermediate for exploratory states, and suppressed during non-exploratory/defensive states. Notably, dopamine release during the predictive CS+ persisted in high fear state and decreased upon extinction, consistent with salience revaluation and an expectation-modulated teaching signal. Together, these results show that BLA dopamine can dynamically weigh external cues and internal states to guide adaptive behaviour. This function has broad implications for grasping how BLA dopamine may support flexible learning and state regulation, and how its dysregulation may contribute to psychiatric disorders such as post traumatic stress disorder (PTSD) and anxiety.